The characteristic of shipping containers that enables their use as structural building blocks is their standardization. From the specifications in ISO 1496-1:1990, the most common standard single container has a length of 40 feet, a width of 8 feet, and a height of 8 feet. Common variations include an alternative height of 9.5 feet, and shorter containers of 20 feet long, and the standards also allow for 30-foot and 10-foot long containers. Their durability is a product of the welded, 2mm Corten steel construction.

Container City I as erected in 2001 consisted of 15 uniform containers, each at 40 feet long, providing a total floor area of approximately 4800 square feet. Each floor is composed of 5 alternating, parallel containers. A later expansion project added 5 containers directly on top, creating a 4th floor and resulting in a total area of roughly 6400 square feet.

Container City II was constructed in 2002 with 30 40-foot containers in a more varied configuration creating 22 studio spaces over its 5 floors, providing approximately 9600 square feet. This project is in a sense an expansion of the more conservative Container City I; containers are not limited to rigid, vertical stacks and whole floors cantilver up to 24 feet with support columns.

While the USM project site for CC1 refers to the fourth floor addition providing "three additional live/work apartments," Eric Reynolds, USM managing director in 2001, says they are "aiming to create cheap but stylish workspaces in a modular fashion." (in an article by David Taylor in the February 8, 2001 issue of The Architects' Journal) The rest of the unfortunately brief article also consistently refers only to workspace or studios. My conclusion then about the distribution of spaces is that the first 3 floors are entirely work/studio space and the new fourth floor is a combination of work and living space.

Also, wrt "How it is Made" in Sean's post below, I can confirm that at least for the first three floors, "the scheme is welded together." (ibid.)

Container City 1 is structurally straightforward: each layer is square, composed of 5 parallel, alternating 40-foot containers. The layout of each floor is evident in the above elevations (ibid.), and the fourth floor addition is externally identical to the second and third floors.

The USM FAQs document states that approximately 300mm pad foundations are necessary at the nodes. The characteristic circular windows visible on both Container Cities is in fact a result of structural engineering: the circular shape doesn't introduce any stress on the structure. Roofing options range from standard flat roofs to green roofs; this accounts for the various rooftop surfaces visible in the following aerial photos, as well as the appearance of the roof of the nearby Riverside Building (the yellow building with a glazed facade facing the river, another USM container building project).